TRIBOLOGICAL BEHAVIOR OF PLA BIODEGRADABLE MATERIALS USED IN THE AUTOMOTIVE INDUSTRY

The use of biodegradable thermoplastic materials
with applicability in various industries such as automotive,
consumer products, medical equipment and others has
increased considerably in recent years. This increase in
demand for biodegradable materials is closely linked to the
growing concerns of producers and consumers alike,
especially with a view to replacing, on a large scale, synthetic
and non-biodegradable polymeric products. This paper
presents the performance of biodegradable polymers PLA,
HD PLA Green and Impact PLA Gray in terms of tribological
properties, the coefficient of friction, wear and their behavior
in different climatic test conditions on equipment that
simulates the operation of the worm-worm wheel assembly
that is part of the drive mechanism of the car wipers. The
highest average value of the wear coefficient and of the wear
track depth was recorded in the case of Impact PLA Gray
sample followed by HD PLA Green and PLA. Regarding the
results of the simulation of the operation within normal gear
parameters of the worm-worm wheel (the worm wheel made
from the materials proposed for this study), it was found that
the mechanism ensures normal operation only for negative
temperatures of use, -10°C being the temperature set as a
standard in the simulations. For the other climatic conditions,
i.e. higher temperatures (18-30)°C, the worm-wheel is not
suitable for use